21131203120 has 40 divisors (see below), whose sum is σ = 49138618320. Its totient is φ = 8451006720.

The previous prime is 21131203117. The next prime is 21131203213. The reversal of 21131203120 is 2130213112.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 21131203094 and 21131203103.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 517035 + ... + 556405.

It is an arithmetic number, because the mean of its divisors is an integer number (1228465458).

Almost surely, 2^21131203120 is an apocalyptic number.

21131203120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131203120 is an abundant number, since it is smaller than the sum of its proper divisors (28007415200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21131203120 is a wasteful number, since it uses less digits than its factorization.

21131203120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46093 (or 46087 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21131203120 its reverse (2130213112), we get a palindrome (23261416232).

The spelling of 21131203120 in words is "twenty-one billion, one hundred thirty-one million, two hundred three thousand, one hundred twenty".